In the air quality directive (2008/EC/50) the EU has set two limit values for sulphur dioxide (SO2) for the protection of human health: the SO2 hourly mean value may not exceed 350 micrograms per cubic metre (µg/m3) more than 24 times in a year and the SO2 daily mean value may not exceed 125 micrograms per cubic metre (µg/m3) more than 3 times in a year.

In the air quality directive (2008/EC/50), the EU has set a target value and a long term objective value for ozone (O3) for the protection of human health. Target value: the maximum daily eight-hour mean may not exceed 120 micrograms per cubic metre (µg/m3) on more than 25 days per calendar year averaged over three years. Long term objective value: the maximum daily eight-hour mean may not exceed 120 micrograms per cubic metre (µg/m3) within a calendar year.

In the directive 2004/107/EC (Fourth Daughter Directive), the EU has set a target value for polycyclic aromatic hydrocarbons (PAH) for the protection of human health; the target is defined in terms of concentration of benzo(a)pyrene (BaP) which is used as a marker substance for PAHs generally: the BaP annual mean value may not exceed 1 nanogram per cubic metre (ng/m3). The target value enters into force 31.12.2012.

"The positive news is that over the last decades, the situation has improved substantially in terms of exposure to several air pollutants. But these pollutants, where we achieved the most significant reductions are not the ones causing most harm to human health and the environment" says Valentin Foltescu, who works on air quality assessment and data reporting at the EEA. We asked Valentin what the EEA does on air quality and what the latest data says.

Ground level ozone causes health problems, decreases crop yields and damages the environment. Ozone levels exceeding certain targets in Europe were less frequent in summer 2011 than in any year since monitoring started in 1997. However, the long-term objective was exceeded in all EU Member States and it is likely many of them will not meet the target value, applicable as of 2010.

This chart shows past emission trends of nitrogen oxides (NOx), sulphur oxides (SOx) and ammonia (NH3) in the EEA-32 and EU-27 group of countries. In addition - for the EU-27 - the aggregated Member State 2010 emission ceilings for the respective pollutants are shown

12 European Cities participating in the Air Implementation Pilot depicting the Air Quality zones and the Urban Audit core city limits. The intention is to show the match between AQ zones and the Urban Audit city limits.